A physics-based model capacity fade analysis of LiMn₂O₄/graphite cell at different temperatures

The capacity fading behavior of a LiMn₂O₄/graphite lithium ion cells at different temperatures is analyzed using a physicsbased porous composite electrode model and a parameter estimation technique. The parameter estimation technique is used to extract capacity fade dependent model parameters from experimental cycling data. Although the capacity fading mechanism of the LiMn₂O₄/graphite lithium ion cells are greatly influenced by temperature, major capacity fading mechanism is closely related to the trapping of Li ions into solid electrolyte interphase on the graphite negative electrode and the reduction in the volume fraction of the active material in the LiMn₂O₄ positive electrode. At 25°C, the dominant capacity fading mechanisms is the formation of the solid electrolyte interphase while at 60°C the dominant capacity fading mechanism is the reduction in the volume fraction of the positive active material. The efficacy of the physics-based composite electrode model is validated with experimental discharge profiles obtained from cells cycled at 25 and 60°C.